This invention relates to a method of and apparatus for providing data relating to an object (herein called object data) by machine vision (as distinct from human vision).
It is known to acquire object data by subjecting the object to illumination (in a broad sense of the term) from an energy source and to produce an image as a result of reflection or interception of the energy, which image can be subject to analysis by machine means (as distinct from human visual perception followed by mental comprehension).
However, such machine vision methods and apparatus, although intrinsically immune to inaccuracy from effects analogous to human fatigue when practiced repeatedly, for example as part of a manufacturing, inspection, investigatory or other field of activity, suffer from certain limitations.
In particular the form of the energy source may preclude or make difficult and expensive detection or determination of certain forms of object data, e.g. the distance of the object from an observation station may not readily be determined by means producing an image of an object illuminated by a light source.
Further, an image produced by illumination of a plurality of objects (like or unlike) by a light source may present difficulty to a machine vision analysing means in selecting a particular one of the objects as the source for derivation of the object data.
The object of the present invention is to retain the advantages of machine vision methods and apparatus while avoiding or reducing limitations such as those mentioned by way of example above.